1. Field of the Invention
The present invention relates to a touch input device. More particularly, the present invention relates to a method for operating a touch input device and a portable terminal using the same that may prevent a malfunction of the touch input device due to an abrupt change of external temperature.
2. Description of the Related Art
In line with a trend of convergence of digital devices, portable terminals are becoming multi-functional devices that integrate diverse functionalities. For example, a recent portable terminal integrates multimedia features such as Audio On Demand (AOD), Video On Demand (VOD), video conferencing, and gaming functions. As the integrated functions are diversified and increased in number, a convenient user interface for enabling a user to control the functions efficiently is becoming increasingly desired, and a touch input device is considered as a promising input device alternative. Since the touch input device enables a user to manipulate data on a screen only with a finger or a stylus, people of all ages and both sexes can use the touch input device. Accordingly, the touch input device is being used in a wide range of applications including banking systems, point-of-sale systems, public information kiosks, tourist information kiosks, and traffic information kiosks. The touch input device inputs a physical change on its screen panel and transmits the physical change to a touch detector. In a capacitive system, a layer that stores electrical charge is placed on a screen panel. When a user touches the screen panel with his or her finger, some of the charge is transferred to the screen panel so the charge on the capacitive layer increases. When the increase of the charge is greater than a threshold value, a touch event has occurred.
Meanwhile, the physical characteristics of the touch input device may change depending on an external temperature. That is, when the external temperature changes abruptly, the variation of the physical characteristic causes a malfunction of the touch input device such that a touch event has occurred. Accordingly, there has been a need to effectively prevent the malfunction of the touch input device.